A mixture containing 1.6 g of 2-amino-4,6-dimethoxypyrimidine, 30 ml of anhydrous methylene chloride and 2.4 g of 2-methoxycarbonylbenzenesulfonylisocyanate was stirred at ambient temperature and pressure for 16 hours. It was then filtered to remove unreacted amine and the filtrate evaporated at temperatures up to 40° and reduced pressure. The residue thus obtained was stirred in 25 ml of water, the pH adjusted to 10 by the addition of 50% aqueous sodium hydroxide and the solution filtered. Acidification of the filtrate to pH 3 caused the formation of a precipitate. Filtration and drying the precipitate yielded 1.7 g of the desired product, melting at 185°-190°. Its infrared absorption peaks at 1700 and 1710 cm-1 are consistent for the desired structure and the nuclear magnetic resonance absorption peaks at 3.8 and 3.85 are consistent for the two different types of methoxy groups brought together in this product.
